Mark Wahlberg wears a Casio W-800H

Sergeant Tommy Saunders never existed. Peter Berg's Patriots Day rebuilds the 2013 Boston Marathon bombing and the manhunt that ended with Dzhokhar Tsarnaev pulled from a boat in a Watertown backyard, and it sticks close to the record except for the cop at its center. Saunders is a composite, invented so that one face could move through the whole story, from the finish line to the shootout to the capture. Mark Wahlberg, who grew up in Dorchester a few miles from where the bombs went off, has been open that the character is a stand-in for many real officers rather than any single one.

The watch on his wrist is harder to pin down. It is a black resin Casio digital, the kind that costs about fifteen dollars, runs a decade on one battery, shrugs off a hundred meters of water, and does little more than light up, time a lap, and count down. Wardrobe-shopping sites that catalog what film characters wear call it the W-800H. No watch publication confirms that, and the movie never lingers on his wrist long enough to read the model, so the specific reference rests on those listings rather than on anything visible on screen. What you can read off the screen is only the type: a plain black digital.